I recently read this Psyche article related to your question. While not an academic paper, they do cite them throughout the article. Here’s the text most relevant to the preserve vs. develop willpower debate:
According to a 2017 meta-analysis of many relevant studies, self-control training seems to be effective at improving ‘self-control stamina’ – the ability to exert inhibitory self-control for longer periods.
So, is that the solution to greater self-discipline? Exercise your self-control muscle and get better at inhibitory self-control?
Unfortunately, it’s not so simple. You might have noticed how I switched back and forth between ‘inhibitory self-control’ and the broader concept of ‘self-control’, but the two are not synonymous. Though boosting your inhibitory self-control or ‘willpower’ might sound appealing – perhaps you imagined yourself using inhibitory self-control to force yourself not to eat the cookies, just like you would if you forced yourself to brush with the opposite hand – it’s not clear that inhibitory self-control actually works this way in everyday life.
Take the findings from a 2017 study that involved volunteers recording their daily experiences of temptation for a week. The individuals who experienced more temptation were less likely to achieve their long-term goals, even if they also reported using more inhibitory self-control. This suggests that using inhibitory self-control to resist those cookies might help you in the moment, but not in the long run. So even if you use inhibitory training (eg, the teeth-brushing challenge) to build a brawny self-control muscle, your heroic efforts are likely to leave you looking more like Sisyphus than Hercules.
I recently read this Psyche article related to your question. While not an academic paper, they do cite them throughout the article. Here’s the text most relevant to the preserve vs. develop willpower debate: